Technical Field
The present disclosure relates to cross-linked polymeric resins comprising anilines linked together with polyamine alkyl chains. Additionally, the present disclosure relates to applications of these cross-linked polymeric resins as agents for the removal of heavy metals, such as lead (II) and arsenic (V) from aqueous.
Description of the Related Art
The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.
Despite the popular knowledge that over two-thirds of the earth's surface area is covered by water, only ˜2.5% of this water is available as freshwater of which 69% is in the form of ice caps and glaciers. The need to recycle the limitedly available water is therefore inevitable as failure to do so poses great health risks. Heavy metals (such as lead and arsenic) disposed in water from various human activities, specifically industrial activities, even at trace levels, are a potential threat to animals and ultimately humans as they are non-biodegradable and their bioaccumulation in the human body can cause various diseases and disorders [S. L. Postel, G. C. Daily, P. R. Ehrlich, Human Appropriation Of Renewable FreshWater, Science (American Association for the advancement of science), 271 (1996) 785-788.; and M. Berger, M. Finkbeiner, Methodological Challenges in Volumetric and Impact-Oriented Water Footprints, Journal of Industrial Ecology, 17 (2013) 79-89.; and S. A. Ali, O. C. S. Al Hamouz, N. M. Hassan, Novel cross-linked polymers having pH-responsive amino acid residues for the removal of Cu2+ from aqueous solution at low concentrations, Journal of Hazardous Materials, 248-249 (2013) 47-58.; and Y. Sun, X. Guan, J. Wang, X. Meng, C. Xu, G. Zhou, Effect of Weak Magnetic Field on Arsenate and Arsenite Removal from Water by Zerovalent Iron: An XAFS Investigation, Environmental Science & Technology, 48 (2014) 6850-6858.; and K. A. Graeme Md, M. D. F. C. V. Pollack Jr, Heavy Metal Toxicity, Part I: Arsenic and Mercury, The Journal of Emergency Medicine, 16 (1998) 45-56.]. Removal of lead and arsenic is achieved by one or more of methods such as chemical precipitation, adsorption, biosorption, electrodialytic processes, ion exchange, ultra-filtration, reverse osmosis, electro-deposition, solvent extraction, foam-floatation, cementation, complexation/sequestration, filtration and evaporation. However, of all of these methods adsorption remains the most attractive due to the availability of several low cost and easily accessible environmentally friendly adsorbents [A. Denizli, K. Kesenci, Y. Arica, E. Pipkin Dithiocarbamate-incorporated monosize polystyrene microspheres for selective removal of mercury ions, Reactive and Functional Polymers, 44 (2000) 235-243.; and Y. Tao, L. Ye, J. Pan, Y. Wang, B. Tang, Removal of Pb(II) from aqueous solution on chitosan/TiO2 hybrid film, Journal of Hazardous Materials, 161 (2009) 718-722.; and O. C. S. Al Hamouz, S. A. Ali, Removal of heavy metal ions using a novel cross-linked polyzwitterionic phosphonate, Separation and Purification Technology, 98 (2012) 94-101.—each incorporated herein by reference in its entirety].
Lead poisoning is a well-known cause of neurobehavorial and cognitive deficits in children and adolescents [J. F. Rosen, Adverse health effects of lead at low exposure levels: trends in the management of childhood lead poisoning, Toxicology, 97 (1995) 11-17.—incorporated herein by reference in its entirety]. A recent study shows that early life exposure to lead poses a threat to fetal outcomes at birth and normal fetal growth [X. Xie, G. Ding, C. Cui, L. Chen, Y. Gao, Y. Zhou, R. Shi, Y. Tian, The effects of low-level prenatal lead exposure on birth outcomes, Environmental Pollution, 175 (2013) 30-34.—incorporated herein by reference in its entirety]. Arsenic has been associated with skin and internal cancer development in humans. Additional non-carcinogenic effects that are associated with arsenic include peripheral neuropathy, diabetes, and cardiovascular diseases [C. O. Abernathy, Y. P. Liu, D. Longfellow, H. V. Aposhian, B. Beck, B. Fowler, R. Goyer, R. Menzer, T. Rossman, C. Thompson, M. Waalkes, Arsenic: health effects, mechanisms of actions, and research issues, Environmental Health Perspectives, 107 (1999) 593-597.].
Polymeric materials based on formaldehyde resins have shown to be an important class of polymers that have been extensively used in a variety of applications. Such applications include insulation material, consolidated wood products, oil filters, abrasive binders, ion exchange membranes and carbon membranes upon carbonization [F. C. Dupre, M. E. Foucht, W. P. Freese, K. D. Gabrielson, B. D. Gapud, W. H. Ingram, T. E. McVay, R. A. Rediger, K. A. Shoemake, K. K. Tutin, J. T. Wright, Preparation of cyclic urea-formaldehyde polymer-modified phenol-formaldehyde and melamine-formaldehyde resin-based binders and their uses, in, Georgia-Pacific Resins, Inc., USA. 1999, pp. 49 pp.; and K. Lenghaus, G. G. Qiao, D. H. Solomon, The effect of formaldehyde to phenol ratio on the curing and carbonisation behaviour of resole resins, Polymer, 42 (2001) 3355-3362.; and N. Kishore, S. Sachan, K. N. Rai, A. Kumar, Synthesis and characterization of a nanofiltration carbon membrane derived from phenol-formaldehyde resin, Carbon, 41 (2003) 2961-2972.—each incorporated herein by reference in its entirety]. Mannich-type polycondensation reactions with formaldehyde have been employed for the production of polymers. Endo, et al. (2009) described the polymerization of a bifunctional benzoxazine from bisphenol-A and aniline with the resulting main chain having a phenolic moiety bridged by a Mannich-type linkage (—CH2—NR—CH2—) [T. Endo, A. Sudo, Development and application of novel ring-opening polymerizations to functional networked polymers, Journal of Polymer Science Part A: Polymer Chemistry, 47 (2009) 4847-4858.—incorporated herein by reference in its entirety]. Altinkok, et al. (2011) also used similar monomers but sulfonediamine was used in place of aniline to prepare polybenzoxazine; however, there is no record of the application of these polyamines to determine their usability or effectiveness as adsorbents for metal ions [C. Altinkok, B. Kiskan, Y. Yagci, Synthesis and characterization of sulfone containing main chain oligobenzoxazine precursors, J. Polym. Sci., Part A: Polym. Chem., 49 (2011) 2445-2450.; and E. Tsuchida, T. Tomono, Polyamine polymers from pyrrole, formalin, and amines by use of the mannich reaction, Journal of Polymer Science: Polymer Chemistry Edition, 11 (1973) 723-735.—each incorporated herein by reference in its entirety]. Barak, et al. (2007) was able to synthesize a new chelating resin from nitrilotriacetic acid (NTA) and melamine using a Mannich-type reaction and subsequently tested it for heavy metal removal from simulated wastewater [A. Baraka, P. J. Hall, M. J. Heslop, Melamine-formaldehyde-NTA chelating gel resin: Synthesis, characterization and application for copper(II) ion removal from synthetic wastewater, Journal of Hazardous Materials, 140 (2007) 86-94.—incorporated herein by reference in its entirety]. Mannich-type polycondensation reactions have enabled researchers to produce polymers with specific functionalities or a combination of several desired functionalities for different applications including removal of heavy metals from wastewater [P. Chutayothin, H. Ishida, Cationic Ring-Opening Polymerization of 1,3-Benzoxazines: Mechanistic Study Using Model Compounds, Macromolecules, 43 (2010) 4562-4572.; and R. N. Singru, W. B. Gurnule, V. A. Khati, A. B. Zade, J. R. Dontulwar, Eco-friendly application of p-cresol-melamine-formaldehyde polymer resin as an ion-exchanger and its electrical and thermal study, Desalination, 263 (2010) 200-210.—each incorporated herein by reference in its entirety].
Many polymers with amine functionality have been reported for removal of heavy metals from wastewater. Gurnule, et al. (2002) studied the ion-exchange properties of a salicylic acid-melamine-formaldehyde terpolymer resin for seven metal ions including Co, Zn, Cu, Ni, Cd, Fe, and Pb ions [W. B. Gurnule, H. D. Juneja, L. J. Paliwal, Ion-exchange properties of a salicylic acid-melamine-formaldehyde terpolymer resin, Reactive and Functional Polymers, 50 (2002) 95-100.]. Singru, el al. (2010) also reported a similar study for the chelating ion-exchange ability of a p-Cresol-melamine terpolymer for these same metal ions. Liu, et al. (2010) functionalized poly(glycidyl methacrylate) (PGMA) beads with four aliphatic amines namely ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), and tetraethylenepentamine (TEPA) and tested them for adsorption of Cu ions; results showed that the DETA-functionalized polymer was superior in adsorption capacity because of the relatively higher amine content [C. Liu, R. Bai, L. Hong, T. Liu, Functionalization of adsorbent with different aliphatic polyamines for heavy metal ion removal: Characteristics and performance, Journal of Colloid and Interface Science, 345 (2010) 454-460.—incorporated herein by reference in its entirety].
Polyaniline, especially, has been one of the most efficient of the chelating ion-exchange polyamines. Recent applications include its use as a component of composites with materials like silica gel, polypyrrole, graphene, etc. [M. Ghorbani, H. Esfandian, N. Taghipour, R. Katal, Application of polyaniline and polypyrrole composites for paper mill wastewater treatment, Desalination, 263 (2010) 279-284.; and X. Liu, Y. Gao, H. Luo, R. Jin, Synergistically constructed polyamine/nanosilica/graphene composites: preparation, features and removal of Hg2+ and dyes from contaminated water, RSC Advances, 4 (2014) 9594.—each incorporated herein by reference in its entirety]. Researchers have even introduced polyaniline coatings on various materials like mesoporous silica, silica gel, jute fiber, and saw dust [R. Ansari, F. Raofie, Removal of Mercuric Ion from Aqueous Solutions Using Sawdust Coated by Polyaniline, E-Journal of Chemistry, 3 (2006) 35-43.; and P. A. Kumar, M. Ray, S. Chakraborty, Hexavalent chromium removal from wastewater using aniline formaldehyde condensate coated silica gel, Journal of Hazardous Materials, 143 (2007) 24-32.; and P. A. Kumar, S. Chakraborty, Fixed-bed column study for hexavalent chromium removal and recovery by short-chain polyaniline synthesized on jute fiber, Journal of Hazardous Materials, 162 (2009) 1086-1098.; and S. Nayab, A. Farrukh, Z. Oluz, E. Tuncel, S. R. Tariq, H.u. Rahman, K. Kirchhoff, H. Duran, B. Yameen, Design and Fabrication of Branched Polyamine Functionalized Mesoporous Silica: An Efficient Absorbent for Water Remediation, ACS Applied Materials & Interfaces, 6 (2014) 4408-4417.—each incorporated herein by reference in its entirety]. However, most of these reports have not explored the use of these materials as adsorbents for heavy metal atoms and ions.
In view of the forgoing, one object of the present disclosure is to provide cross-linked polymeric resins formed from by reaction of aniline, one or more diaminoalkane monomers and an aldehyde to provide a polymeric material with improved amine chelate-forming functionality, and their spectroscopic characterization. Another object of the present disclosure is to provide a process for producing the cross-linked polymeric resins by the use of a Mannich-type polycondensation between an aniline compound and a diaminoalkane compound in the presence of an aldehyde and subsequent basification. In addition to the cross-linked polymeric resins and methods for their preparation, the present disclosure further aims to provide methods for efficiently removing heavy metals, such as lead (II) and arsenic (V) ions, from an aqueous solution by employing the adsorbent properties, examined by kinetic, diffusion, isotherm, and thermodynamic models, of the cross-linked polymeric resins described herein.